1. Field
One or more embodiments of the present invention relate to a secondary battery.
2. Description of the Related Art
In general, unlike primary batteries which are not rechargeable, a secondary battery is both dischargeable and rechargeable. A secondary battery is used as an energy source of, for example, a mobile device, an electric vehicle, a hybrid vehicle, an electric bicycle or an uninterruptible power supply (UPS). Based on the type of external device used with the batteries, a single secondary battery may be used or a battery module in which a plurality of batteries are bundled up by electrically connecting the batteries may be used.